This invention relates to an apparatus and method for raising and supporting a building, and more particularly to such an apparatus and method in which pilings are used to support the foundation or concrete slab of a building.
Houses and other buildings are often erected on foundations or concrete slabs which are not in direct contact with load supporting underground strata, such as bedrock, or the like. If not initially constructed properly, or if soil conditions change, the foundation footing may settle, causing the foundation or slab to sag and/or crack. Unless the building is supported, or shored, continued settling may result in major structural damage or collapse of the building.
There have been several suggestions in the prior art for raising and supporting the foundation or slab of a building of this type. For example, according to one technique the foundation or slab is lifted, or jacked up, and pilings are inserted underneath to support same. However, the pilings are often not directly supported on the bedrock, resulting in continued settling after the pilings are in place. Also, these techniques often require extensive evacuation of the basement flooring for placing the pilings under the foundation walls, which is expensive. Further, in many instances, the pilings are visible above the basement floor.
In still other prior art techniques utilizing pilings, a single hydraulically actuated system is used for each piling requiring the use of a relatively high hydraulic pressure system which is expensive add cumbersome to use. Also, if the pilings are lifted individually, the structure of the foundation or slab becomes uneven which causes additional potential problems.
Also, according to many prior art techniques the pilings have to be mechanically attached to the raised foundation or lifting bracket after the foundation has been lifted, which requires time and skilled labor.
Still additional problems are encountered when sleeve type brackets are used to apply a concentric, asymmetrical load to a piling, since in these systems the piling tends to buckle. When symetrical loads are applied they have to be bolted to the foundation which requires expensive epoxy bolts, which tend to rip out from weak concrete. Also, these systems are time-consuming to install and must be fastened to the face of the foundation and thus often have to be exposed above grade when used with relative shallow foundations.